Chapter 2 AI generated Flashcards
Describe the components of the innate immune system mentioned in the content.
The innate immune system includes complement proteins, professional phagocytes, and natural killer cells.
Define the complement system and its role in the immune response.
The complement system consists of about 20 different proteins that work together to destroy invaders and signal other parts of the immune system. It can be activated in three different ways.
How does the alternative pathway of the complement system function?
In the alternative pathway, the complement protein C3 is cleaved into C3a and C3b. C3b binds to the surface of invaders, initiating a chain reaction that leads to the destruction of the invader.
What is the role of the MAC (membrane attack complex) in the immune response?
The MAC, formed by C5b, C6, C7, C8, and C9, creates a hole in the surface of invaders, leading to their destruction.
Describe the lectin activation pathway of the complement system.
The lectin activation pathway relies on the protein MBL (mannose-binding lectin) to recognize mannose on pathogen surfaces and initiate the immune response.
How do complement proteins protect our own cells from being attacked by the immune system?
Proteins like MCP enzyme, DAF protein, and CD59 act as safeguards to prevent the incorporation of C9 molecules and protect our own cells from immune attack.
Describe the three main functions the complement system.
1 Building membrane attack complexes (MACs)
2. Opsonizing invaders: C3 → iC3bn
3. Serving as chemoattractants: C3a and C5a
What are the two types of professional phagocytes mentioned in the content?
Macrophages and neutrophils
Define hyperactivation in the context of macrophages.
Hyperactivation occurs when macrophages receive a direct signal from an invader, leading them to stop proliferation and focus solely on killing.
How do neutrophils contribute to immune response?
Neutrophils phagocytose, kill efficiently, produce cytokines, and release destructive chemicals.
Describe the role of IFN-y in activating macrophages.
IFN-y is a cytokine mainly produced by Th-cells and NK-cells that signals macrophages to become activated and upregulate MHC II for better antigen presentation.
What is the approximate half-life of neutrophils in the blood?
Approximately 5 days
How do macrophages differ in function between their resting state and activated state?
In the resting state, macrophages primarily act as garbage collectors, while in the activated state, they become good presenters and killers.
Define opsonization in the context of the complement system.
Opsonization is the process by which C3b attaches to an invader, enhancing its grip and making it easier for phagocytes to engulf and destroy the target.
Describe the role of NK in the immune system.
NK cells are activated by IFN type I or LPS and identify their targets through activating receptors on the surface of a target cell. They can proliferate under the influence of IL-2.
